A pitot tube or probe is typically mounted on a vehicle and measures the velocity of a vehicle relative to a fluid in which the vehicle is moving. In one application, a pitot probe is mounted upon an aircraft and measures the velocity of the aircraft relative to the air mass during flight. Pitot probes generally include a hollow tube that defines an open end pointing in the direction of fluid flow or vehicle movement. The hollow tube of the pitot probe contains a fluid, such as air in the case of an aircraft. The pressure within the pitot probe provides a stagnation pressure measurement, which is also called total pressure. The total pressure is combined with a static pressure, which is typically measured at a different location on the aircraft fuselage, or on the side of the pitot probe in the case of a combined pitot-static probe, in order to determine an impact pressure. The impact pressure is used to determine the airspeed of the aircraft.
Sometimes pitot probe based airspeed systems may produce incorrect airspeed readings. The incorrect reading may be caused by issues such as probe contamination, damage to the probe, or maintenance issues. Some examples of probe contamination include, but are not limited to, ice, volcanic ash, and insect invasion. Systems that estimate airspeed based on a model of an aircraft currently exist, however these systems may not be able to robustly calculate an accurate airspeed during some types of operating conditions. More specifically, these systems may not be able to calculate accurate airspeeds during high speed flight regimes, especially at transonic Mach numbers. Also, the airspeed calculated by the system may be susceptible to variations of a sensed angle of attack of the aircraft. Finally, the airspeed may also be susceptible to any discrepancies of a lift model, even in regimes where it is possible to calculate accurate airspeeds.